Just to let you know that this Sunday (5th) the BBC Radio's Living World programme is about the "native" Pool Frog re-introduction conservation project. Interviewer Joanna Pinnock will be talking to John Baker, who was involved in the re-introduction and has been monitoring the site since.It's being broadcast at 6.35am on BBC Radio 4 but will also be available afterwards on the BBC I player page http://www.bbc.co.uk/programmes/b007qyz3.Beforehand there's a piece about it with some photos on The Living World webpage http://www.bbc.co.uk/programmes/b01lh96b

The programme is now available to listen to on the BBC I player for those not up at 6.30 this morning. Interesting that they are also monitoring the grass snake population on the site to see how many individual snakes are there and whether they are likely to have a significant effect on the frogs. Seems the herons are also hanging around to pick up a meal.Might be several years still before it's known whether the attempt to re-introduce the species has been a success or not.

Is it not natural that grass snakes will predate any frog population? If they were to be assessed as having some sort of impact what would be the options?

It seems to me that every healthy common frog or common toad population I know has a reasonable number of grass snakes present, one follows the other. If the Pool Frog introduction is actually a success then the fact that they support a grass snake population (perhaps even an increasing one) would in my opinion be ecologically 'normal'.

Agree with Gemma. Isn't a natural balance best? Smooth snakes eat sand lizards don't they? Grass snakes eat frogs - not fussy on type presumably. I hope there is no intention to try and tip the balance in favour of the Pool Frog.

My thoughts too, if 'control' of the grass snakes is thought of as an option, it would in my opinion be the ultimate act of 'pet keeping' and in my mind would completely invalidate the 'success' of the reintroduction.

If the frogs cannot withstand natural predation one would have to really consider if the correct site was chosen or if the project was actually really a 'success' in ecological terms.

Of course the population must be able to withstand natural predation in the long-term, but I would assume it would take several years for what is essentially an unnatural population to develop the structure and dynamics of a natural population that would be able to cope with predation.

So would you advocate the 'control' of native snakes to encourage the growth of a non-native population of animals? Not picking a row with you, I'm genuinely interested in peoples views. To me it's seems like just one step too far but that may not be everyone's view on the subject.

I've heard of similar monitoring of grass snakes around natterjack populations but to me if grass snakes (which feed infrequently) are really that much of a threat what hope have these small populations got against heron, rats, foxs natural events etc?

I wonder have there been any cases where grass snakes have been moved away or culled in the process of amphibian conservation that anyone knows of?

What is the biggest gripe on here? Management of sites to benefit particular species (to the detriment of others). When does a leg up for one or two species become very bad news for many others? If it's a reintroduction then the question is why they died out in the first place. What looks OK habitat to us is irrelevant surely as we can't possibly know all the requirements of of these frogs. With all best intentions I don't think overall, barn owl reintroductions can be considered a success, as an example, because we just don't know.

Too true, I think it is very fair to say that real ecosystems are in all cases far too difficult to understand or predict and in nearly all cases attempts to modify them fail or backfire.

For example what happens if the grass snakes were removed and the Pool Frogs then face competition from an explosion of native amphibians?

Should they then also be moved/culled to protect the re-introduced frogs? I've heard that the original reason for the extinction was a lack of management and collection. I guess these issues have been addressed and I'm sure we all appreciated the effort put into the project but it does raise an interesting issue of how far we should go with manipulating things.

The URL to listen to the programme is http://www.bbc.co.uk/iplayer/console/b01lh96b . There was no suggestion in the programme that grass snakes (or heron or otter) were to be controlled, merely that they were being monitored. They did say that the pool frog population is increasing gradually, rather than rapidly exploding. The grass snake population at the site is apparently also increasing.

The reasons for the original extinction are pretty well known- basically drainage of the Fens reduced them to a few isolated colonies, then lowering of the water table during the 1980s and 90s killed them off at the last site.

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